The lipid-metabolism enzyme ECI2 reduces neutrophil extracellular traps formation for colorectal cancer suppression

TiO2-coated honeycomb-like super-macroporous silica for high-purity extraction of exosomes from human plasma

Screening biomarkers from exosomes has emerged as a new strategy for non-invasive early diagnosis of diseases. Nevertheless, the present screening efficiency and accuracy of biomarkers are limited by the low extraction efficiency and purity of exosomes. To address this issue, a highly selective adsorbent, which integrates size-exclusion and chemisorption, was created by coating TiO2 on honeycomb-like super-macroporous silica. Cell culture medium and human plasma were employed to investigate the enrichment performance, and the results indicate that the super-macropores ranging from 63.5 to 147.5 nm together with thin pore walls allow exosomes to enter and be adsorbed by TiO2 in the pores, enhancing the available surface area for exosomes meanwhile physically excluding the large-sized cell debris and vesicles. Taking advantages of these properties, the prepared adsorbent achieves a higher extraction efficiency, recovery and purity of exosomes compared with the normal adsorbents and ultracentrifugation (UC) method. Combining this method with proteomic analysis, a total of 392 proteins were identified in exosomes from healthy human plasma, which is significantly higher than the number obtained by UC (200 proteins). For clinical samples, 59 upregulated and 124 downregulated proteins were identified in the plasma from colorectal cancer (CRC) patients, of which 44 upregulated proteins and 69 downregulated proteins are strongly associated with the progression of CRC. These findings suggest that this adsorbent possesses considerable potential in the extraction of exosomes for screening biomarkers and diagnosing tumor progress.

From Ulcerative Colitis to Metastatic Colorectal Cancer: The Neutrophil Contribution

Ulcerative colitis (UC) is an inflammatory colon and rectum disease affecting approximately 5 million people worldwide. There is no cure for UC, and approximately 8% of patients with UC develop colorectal cancer (CRC) by gradual acquisition of mutations driving the formation of adenomas and their progression to adenocarcinomas and metastatic disease. CRC constitutes 10% of total cancer cases worldwide and 9% of cancer deaths. Both UC and CRC have an increasing incidence worldwide. Although the epithelium has been well studied in UC and CRC, the contribution of neutrophils is less clear. Neutrophils are rapidly recruited in excessive amounts from peripheral blood to the colon during UC, and their overactivation in the proinflammatory UC tissue environment contributes to tissue damage. In CRC, the role of neutrophils is controversial, but emerging evidence suggests that their role depends on the evolution and context of the disease. The role of neutrophils in the transition from UC to CRC is even less clear. However, recent studies propose neutrophils as therapeutic targets for better clinical management of both diseases. This review summarizes the current knowledge on the roles of neutrophils in UC and CRC.

Immunometabolism of Innate Immune Cells in Gastrointestinal Cancer

Cancer cells are often described as voracious consumers of nutrients, with glucose frequently cited as a key energy source; however, their metabolic plasticity allows them to adapt and utilize various substrates, including lipids and amino acids, to sustain growth and survival. However, the metabolic demands of immune cells within the tumor microenvironment (TME) are less commonly discussed despite their critical role in shaping the immune response. In this review, we explored the intricate interplay between immunometabolism and innate immunity cells in gastrointestinal cancers. We focused on how metabolic pathways, including glycolysis, fatty acid oxidation, and amino acid metabolism, drive the immunosuppressive functions of myeloid-derived suppressor cells (MDSCs) and tumor-associated neutrophils (TANs), tumor-associated macrophages (TAMs) and innate lymphocyte subsets such as NK cells. These cells contribute to a hostile immune landscape, supporting tumor growth and evasion from immune surveillance in a phenomenon of tumor-derived immunosuppression. Additionally, we investigated the influence of dietary interventions on the metabolic reprogramming of these immune cells, highlighting how nutrition can modulate the TME. Finally, we discussed emerging therapeutic strategies that target metabolic vulnerabilities in MDSCs, TANs, NK cells, and monocytes, offering a novel avenue for enhancing antitumor immunity. By dissecting these mechanisms, we aim to provide insights into how metabolic pathways can be harnessed to improve cancer treatment outcomes. This review underscores the importance of understanding immunometabolism not only as a driver of immune suppression but also as a potential therapeutic target in gastrointestinal cancer.

Metabolic reprogramming of tumor-associated neutrophils in tumor treatment and therapeutic resistance

Tumor-associated neutrophils (TANs), pivotal immune cells within the tumor microenvironment (TME), exhibit dual potential in both pro- and anti-tumorigenic effects. These cells display remarkable heterogeneity and plasticity within the TME, adapting to hypoxic and nutrient-deprived conditions through metabolic reprogramming while critically influencing tumor progression, metastasis, and immune evasion. The metabolic reprogramming of TANs not only modulates their functional phenotypes but also reshapes tumor biological behaviors and therapeutic responses by regulating metabolic intermediates and cellular interactions within the TME. Therefore, elucidating the mechanisms underlying TANs metabolic reprogramming has significant implications for deciphering the molecular basis of tumorigenesis, identifying novel therapeutic targets, and optimizing immunotherapeutic strategies. This review systematically summarizes current knowledge regarding metabolic reprogramming mechanisms of TANs in the TME and their impact on tumor progression. We particularly focus on: 1) TAN-specific alterations in glucose, lipid, and amino acid metabolism within the TME; 2) Emerging immunotherapeutic strategies targeting TANs metabolic pathways; 3) Recent advances in understanding TAN-mediated immune evasion and therapy resistance. Furthermore, this review discusses potential challenges and corresponding solutions in targeting TANs metabolic reprogramming for therapeutic intervention, aiming to provide novel insights for advancing cancer immunotherapy.

Nuclear receptor 4A1 is critical for neutrophil-dependent pulmonary immunity to Klebsiella pneumoniae infection

Introduction

Bacterial pneumonia is a burdensome, costly disease and increasingly challenging to treat due to antibiotic resistance. Complex host-pathogen interactions regulate protective immunity. Neutrophils play a central role in pulmonary bacterial immunity, and mechanistic understanding of neutrophil functions in bacterial pneumonia has potential clinical and fundamental application. Nuclear receptor 4a1 (Nr4a1), a member of the nuclear orphan receptor family, has been described to regulate inflammation and immune development in a cell type-specific manner, but its role in pulmonary host defense is not well understood.

Methods

Wild-type (WT) and Nr4a1-/- mice, as well as bone marrow chimeric and Gr-1+ antibody depleted mice, were infected with Klebsiella pneumoniae and assessed for bacterial burden in the lung and spleen, gene transcription, protein levels, histology and cellular abundance by flow cytometry in the lung. WT and Nr4a1-/- neutrophils were exposed to live Klebsiella pneumoniae to quantify bacterial killing, as well as bulk RNA sequencing to assess transcriptomic differences.

Results

Nr4a1-deficient mice are highly susceptible to Klebsiella pneumoniae pneumonia, which was mediated by Nr4a1 expression in immune cells. Gr-1+ antibody depletion ameliorated the Nr4a1-dependent phenotype. Ex vivo, Nr4a1-deficient neutrophils had impaired bactericidal capacity, and transcriptomic analysis identified an Nr4a1-dependent host defense program in neutrophils.

Discussion

Neutrophil Nr4a1 expression is critical for defense against K. pneumoniae infection by regulating the neutrophil transcriptome. These findings suggest targeting Nr4a1 signaling pathways in neutrophils may be useful for bacterial pneumonia treatment.

Oxidative Stress and Reprogramming of Lipid Metabolism in Cancers

Oxidative stress is a common event involved in cancer pathophysiology, frequently accompanied by unique lipid metabolic reprogramming phenomena. Oxidative stress is caused mainly by an imbalance between the production of reactive oxygen species (ROS) and the antioxidant system in cancer cells. Emerging evidence has reported that oxidative stress regulates the expression and activity of lipid metabolism-related enzymes, leading to the alteration of cellular lipid metabolism; this involves a significant increase in fatty acid synthesis and a shift in the way in which lipids are taken up and utilized. The dysregulation of lipid metabolism provides abundant intermediates to synthesize biological macromolecules for the rapid proliferation of cancer cells; moreover, it contributes to the maintenance of intracellular redox homeostasis by producing a variety of reducing agents. Moreover, lipid derivatives and metabolites play critical roles in signal transduction within cancer cells and in the tumor microenvironment that evades immune destruction and facilitates tumor invasion and metastasis. These findings suggest a close relationship between oxidative stress and lipid metabolism during the malignant progression of cancers. This review focuses on the crosstalk between the redox system and lipid metabolic reprogramming, which provides an in-depth insight into the modulation of ROS on lipid metabolic reprogramming in cancers and discusses potential strategies for targeting lipid metabolism for cancer therapy.

CRIP1 inhibits cutaneous melanoma progression through TFAM-mediated mitochondrial biogenesis

Metastasis is the leading cause of death in patients with cutaneous melanoma. CRIP1 (cysteine-rich protein 1) has been reported to be associated with malignant progression of several cancers. However, the biological function and underlying mechanisms of CRIP1 in melanoma progression are largely unknown. Bioinformatic prediction of CRIP1 expression in melanoma and its association with clinical parameters and prognosis of patients. Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blots (WB) were used to detect stable overexpression and knockdown of CRIP1 in melanoma cells. The function of CRIP1 in cutaneous melanoma cells was determined by in vitro functional assays. WB, immunofluorescence, OCR detection, mitochondrial DNA assay, and cytosolic ATP assay were used to determine the relationship between CRIP1 and mitochondrial biogenesis, relationship between TFAM. The expression level of CRIP1 in melanoma tissues is lower than that in normal tissues and suggests a poor prognosis for melanoma patients. Functionally, CRIP1 inhibits the proliferation, migration, and invasion of melanoma cells in vitro. Mechanistic studies revealed that CRIP1 inhibited mitochondrial biogenesis in melanoma cells, which included suppression of relative mitochondrial content, mitochondrial DNA copy number, ATP production, respiratory capacity, and expression levels of oxidative phosphorylation-related proteins. Further studies revealed that CRIP1 inhibits mitochondrial biogenesis and malignant progression in melanoma cells by suppressing the protein levels of TFAM. Our results suggest that CRIP1 inhibits the proliferation and invasive ability of cutaneous melanoma cells by suppressing TFAM-mediated mitochondrial biogenesis. Therefore, CRIP1 may be a potential therapeutic target for melanoma.

The success of the tumor immunotherapy: neutrophils from bench to beside

The present immune therapy was focused on the immune checkpoint blockade or Chimeric Antigen Receptor T-Cell Immunotherapy (CART) transfer, but how to activate the innate immune system to antitumor still lags out. Neutrophils are the most abundant circulating leukocytes in human, and heterogeneous neutrophils have been increasingly recognized as important players in tumor progression. They play double "edge-sward" by either supporting or suppressing the tumor growth, including driving angiogenesis, extracellular matrix remodeling to promote tumor growth, participating in antitumor adaptive immunity, or killing tumor cells directly to inhibit the tumor growth. The complex role of neutrophils in various tumors depends on the tumor microenvironment (TME) they are located, and emerging evidence has suggested that neutrophils may determine the success of tumor immunotherapy in the context of the immune checkpoint blockade, innate immune training, or drug-loaded extracellular microvesicles therapy, which makes them become an exciting target for tumor immunotherapy, but still with challenges. Here, we summarize the latest insights on how to activate neutrophils in antitumor immunity and discuss the advances of neutrophil-targeted immunotherapy strategies.

IL-1β-induced epithelial cell and fibroblast transdifferentiation promotes neutrophil recruitment in chronic rhinosinusitis with nasal polyps

Neutrophilic inflammation contributes to multiple chronic inflammatory airway diseases, including asthma and chronic rhinosinusitis with nasal polyps (CRSwNP), and is associated with an unfavorable prognosis. Here, using single-cell RNA sequencing (scRNA-seq) to profile human nasal mucosa obtained from the inferior turbinates, middle turbinates, and nasal polyps of CRSwNP patients, we identify two IL-1 signaling-induced cell subsets-LY6D+ club cells and IDO1+ fibroblasts-that promote neutrophil recruitment by respectively releasing S100A8/A9 and CXCL1/2/3/5/6/8 into inflammatory regions. IL-1β, a pro-inflammatory cytokine involved in IL-1 signaling, induces the transdifferentiation of LY6D+ club cells and IDO1+ fibroblasts from primary epithelial cells and fibroblasts, respectively. In an LPS-induced neutrophilic CRSwNP mouse model, blocking IL-1β activity with a receptor antagonist significantly reduces the numbers of LY6D+ club cells and IDO1+ fibroblasts and mitigates nasal inflammation. This study implicates the function of two cell subsets in neutrophil recruitment and demonstrates an IL-1-based intervention for mitigating neutrophilic inflammation in CRSwNP.